In checking water, oil, gas or other pipe lines or conduits for leaks, or for other purposes, or for repairing or replacing pipe line sections it was at one time the practice to drain off part of the line, or to sever the pipe and cap the exposed end thereof with a plate or other similar cover. This is a time consuming and expensive procedure.
More recently the accepted method has been to freeze a section of the pipe, a water pipe, for instance, without cutting it or draining it of its contents; and therefore testing or repairing or working on that portion of the pipe line which is located "down stream" of the frozen pipe section. After the testing, repairs or pipe work or replacement has been completed, the section that was frozen and its contents are permitted to thaw thus resuming the flow of water through the pipe line as a whole.
One such method of freezing the contents of the pipe, was to use a pipe freezing device having a "U" shaped section or unit that straddled the pipe. The "U" shaped freezing unit acts as an evaporator and is connected to a conventional refrigeration system having a compressor, condenser and piping containing a metering device. The "U" shaped pipe freezing unit has a hollow chamber to which the refrigerant is pumped under pressure. In the interior space the refrigerant evaporates into a vapor state, also referred to as gas, and draws heat away from the pipe and then cools the contents in the pipe to below freezing temperature. The vapor passes out of the freezer unit and returns to the compressor. The space or gap between the pipe and the "U" shaped section is filled with a gel bag or water. The water and/or gel bag transfers the heat from the pipe. U.S. Pat. No. 4,309,875 discloses such a freezer, and is incorporated herein by reference.
One of the short comings of the prior freezing device is that water or some other freezable gel is needed to fill the space between the "U" shaped freezer unit and the pipe. It is desired to have an evaporator which would fit to various size pipes.